The use of various fastening devices for rejoining bones which have become fractured is well-known. A common example of the same is the "locked" nail which comprises a predetermined length of rod having apertures for transverse locking screws at both ends. Another example is modular nails which comprise a pair of interlocking tubular members adapted to be inserted in the intramedullary passages of the parts of a fractured bone; they are quite expensive, but do reduce the number of devices required to fit all patients. Another intramedullary nail device includes an extended tubular shaft having a predetermined cross-section having transverse apertures at various locations along its length. Such a device is inserted into an intramedullary cavity of a bone and secured within the bone by transverse bone screws placed through an aligned aperture in the device.
An intramedullary device which can be adjusted in length after installation, is disclosed by Bradshaw in U.S. Pat. No. 4,946,459. This intramedullary device comprises, a slotted nail member which extends toward the distal end of the bone, and is affixed at the distal end by means of pins or screws extending through the bone. At the proximal end of the nail is an interiorly spliced receptacle affixed to the end of the nail. The spliced receptacle has an interior shoulder therein approximately mid-way of its length. An exteriorly spliced adjustment shaft is adapted to fit into the spliced receptacle and to bear against the shoulder thereof. The shaft is mounted within an elongated cylinder having an interiorly spliced end cap at its distal end whereby the shaft is free to slide within the cylinder but is restrained from rotation with respect thereto. The interior of the cylinder is threaded over a major portion of its length from the proximal end toward the spliced end cap. The proximal end of the shaft has a stop collar mounted thereon to prevent the shaft from sliding out of the cylinder through the end cap, but to permit insertion and removal of the shaft through the proximal end of the cylinder. An adjustment screw is threaded into the threaded cylinder and is adapted to bear against the stop collar. The screw has a socket, such as a hexagonal Allen socket, in its proximal end to permit driving the screw into the cylinder, and hence driving the spliced shaft toward the distal end of the bone, which in turn drives the nail toward the distal end away from the cylinder. A cylindrical end cap having external threads thereon is threaded into the cylinder after the adjusting screw has been inserted therein. Mounted to the end cap extending therefrom is a longitudinal section of biocompatible tubing. Such devices, however require transcutaneous adjustment to achieve lengthening.